car problem (real head scratcher)

[Ford SD]

My 2005 Lincoln Towncar (104,000 miles) bucks at approx. 40 MPH when I give it the gas. No codes show up. If I turn off the overdrive it doesn't happen.
Trusted mechanic said it's probably the transmission (he described what he thought was the problem).
Transmission guy said it sounds like a misfire.
Any ideas?

Low cost temp fix is to pull each if the 8 plugs off the coils one at a time and use a small fine (clean oil free) 1/4 x 1/16 flat file and clean the corosion off the top and bottom of the contacts ... compressed air to clean up and reinstall
I have also seen where the top of the coil is cracked and moisture can get in

Most likely the ones closest to the edge of the hood is bad... water drips down

Better fix ..Go to Rockauto

Best place for 8 new coils plus
8 new plugs

it woulds happen to the ford superduty I was driving ... bad coils if you replace all 8 you should be good for another few years

[Battis]

I hooked up my high tech OBD2 scanner (from Amazon) after it ran really bad and it showed PO303 - cylinder misfire. Little bugger.

[s mac]

There you go.

[6bg6ga]

Low cost temp fix is to pull each if the 8 plugs off the coils one at a time and use a small fine (clean oil free) 1/4 x 1/16 flat file and clean the corosion off the top and bottom of the contacts ... compressed air to clean up and reinstall
I have also seen where the top of the coil is cracked and moisture can get in

Most likely the ones closest to the edge of the hood is bad... water drips down

Better fix ..Go to Rockauto

Best place for 8 new coils plus
8 new plugs

it woulds happen to the ford superduty I was driving ... bad coils if you replace all 8 you should be good for another few years

I still question the legitimacy of replacing all 8 coils. In my Envoy I knew I had a bad coil per the scan tool and replacing the plug to find the miss still there. It was a simple matter to replace the offending coil at $80. I replaced number 1 and 2 simply because the record indicates they are the ones that have a problem on the inline 6.

Ford's generally have a problem with the coils that get dripped on from the AC line/moisture/ condensation. I went thru (4) Ford vans in 20 years so I can tell you which cylinders coils are subject to having to be replaced because Ford never corrected the situation in all that time. Anyway there are 2) coils that go to hell as a result of drippage from the AC lines. IN ALL the time I drove the Fords I never lost any other coil pack thus the reason to question the replacement of all eight coil packs. I drove each Ford van to almost 300,000 miles and I lost the two coil packs on each of the Ford vans the same two. I can see the eight plugs since you are going to the bother of working on it anyway.

Good for you on your Amazon scan tool generally the cheap ones are prone to showing questionable codes.

[Battis]

If I could do the work myself, I'd probably do all 8. Since we got the Buick, the Lincoln is #2 car and not driven much. I just got rid of my 2001 Lincoln Towncar with 227,000 miles on it. Lincoln Towncars - they've been called bookie cars, pimp mobiles, and just old people cars. I call them comfortable as heck.

[brass410]

how about that ? misfire did it give a specific cyl or just misfire? if you have a shop/mech that you trust they can scan with a live data scan and it will show specifics like cyl or random misfire counts, this will help narrow down specifics. As to replaceing plugs it would probably be a good idea as some of these engines are notorious for seizing plugs at high mileage making a tune up into a cyl head replacement job, we just love it when guy's come in bragging how long they went ( without at least pulling plugs for inspection) because the owners manual says you can, job goes from a couple hundred dollars to several thousand. Technically they don't sieze rather they get a heavy coating of carbon on the tip causing it to break off in the cyl head. If you find which cyl has misfire (if just one) you can trade coil with nieghbouring cyl and see if misfire moves to new cyl(will still need scan tool) if it does its probably the coil if it doesn't its more likely the plug.

[6bg6ga]

how about that ? misfire did it give a specific cyl or just misfire? if you have a shop/mech that you trust they can scan with a live data scan and it will show specifics like cyl or random misfire counts, this will help narrow down specifics. As to replaceing plugs it would probably be a good idea as some of these engines are notorious for seizing plugs at high mileage making a tune up into a cyl head replacement job, we just love it when guy's come in bragging how long they went ( without at least pulling plugs for inspection) because the owners manual says you can, job goes from a couple hundred dollars to several thousand. Technically they don't sieze rather they get a heavy coating of carbon on the tip causing it to break off in the cyl head. If you find which cyl has misfire (if just one) you can trade coil with nieghbouring cyl and see if misfire moves to new cyl(will still need scan tool) if it does its probably the coil if it doesn't its more likely the plug.

My experience here....The cheap scan tools don't do everything the better ones do. I've encountered random codes on the cheap scan tools that were checked against a decent scan tool. I will admit it is possible to purchase a scan tool that actually works correctly without throwing random codes. I will admit I don't own one and I count on my son who is a GM master world class tech to bring his scan tool to check my vehicles. There was an instance where the Caddy threw a code and I had it checked by the local parts house and then checked with my son's Mac scan tool. The Mac told me exactly the sensor that was faulty and the parts house threw a random mixture code.


As for the spark plug mileage ..... My instance I was a technician that spent hours on the road everyday thus it took quite an undertaking to get the van into a shop to get repaired. My comment on the miles wasn't necessarily to encourage others to exceed the 100K general spark plug life. My experience here again based on my vehicle and the company van I drove is the plugs generally come out easy up to about 120K miles and after that difficulty starts to set in. In my instance my former boss didn't care about getting a vehicle in at say 80K to change plugs because every hour I was off the road he lost $100 in revenue therefore he probably figured that $300 down the road to change plugs when my schedule was less booked was better than say a $80 bill to change plugs when I was booked solid.

I keep a spare GM colil for the Envoy and the SRX on the shelf as a backup for my misfire problems that might arise in the future and I wholeheartedly agree with switching the suspected bad coil with another coil in tracking the misfire and as mentioned a scan tool is needed in order to see if the fault followed the coil. Glad you got it figured out at any rate.

[Battis]

The reason I trust the mechanic is that he's not a parts swapper. There are others in town that just replace parts until they find the problem. The Lincoln had a bad coil last summer and it eventually showed on my scanner, and it was confirmed by the mechanic. He replaced it, and it's been fine.
The code on the scanner I used read PO303, which indicates a misfire in that cylinder. It's going to the shop tomorrow and they'll confirm it before replacing it.

[dangitgriff]

[Battis]

The last car thread I started was about the tires on my Buick, which is apparently the worse car to own. I'm curious to see if this thread takes off like that one did.

[merlin101]

My 2005 Lincoln Towncar (104,000 miles) bucks at approx. 40 MPH when I give it the gas. No codes show up. If I turn off the overdrive it doesn't happen.
Trusted mechanic said it's probably the transmission (he described what he thought was the problem).
Transmission guy said it sounds like a misfire.
Any ideas?

Fuel pump! It's electronic and in the fuel tank, been down that road a couple times and was also told it was the tranny. After checking the fluid and seeing the color and no brunt smell I checked the fuel pressure and it was fluctuating, new pump fixed everything.

[6bg6ga]

The last car thread I started was about the tires on my Buick, which is apparently the worse car to own. I'm curious to see if this thread takes off like that one did.

Want to dig up the Buick thread again?

[Battis]

Nope. New tires, no problems, love that Buick.

[Finster101]

The last car thread I started was about the tires on my Buick, which is apparently the worse car to own. I'm curious to see if this thread takes off like that one did.

Nope, I'm a GM tech but I like Town Cars. My Dad had several of them over the years and I had an 03 Mercury Marauder. All were prone to TCC shudder if the trans fluid wasn't changed about every 50k or so. Very common, hence my suggestion to have it done. Hard to diag over the internet though since often several problems can present with the same symptoms. Kinda like them TV preachers trying to swammy out your ailments and heal you at home for a small contribution.

[skeettx]

Waiting on the final answer
Good luck
Mike

[rdwarrior]

I had a similar problem with my 200 Ford F-150 a month ago. I also thought it was the transmission as it didnt act up with overdrive turned off. I changed the plugs and rebuilt the coil packs. runs like a dream again. It was misfiring, but with over drive off, it kept the rpms up so it didnt act up, making me think it was the transmission. change the plugs and rebuild the coil packs and I would be willing to bet all your problems go away.

[tomme boy]

I worked at Autozone part time last year for something to do. DO NOT GET YOUR PARTS FROM AUTOZONE!!!

If it is a Autozone branded part go something else. Look for name brand on your parts. I got so mad at all the junk that they sell that I was telling people to go somewhere else if i could not get a name brand part. Like TRW, MOOG, Bosch...... Some of the cheaper batteries would fail in a few days. You have to buy their most expensive store brand to get a good one. Alt, starters, coils, sensors, lots and lots bad right out of the box.

Granted, they will keep replacing the parts till you get a good one. But who wants to go through that? I had to quit as I could not take the rip offs anymore.

The code reader is a very basic thing and is meant to sell you parts. It only gives basic codes. It will not tell you what coil is bad or how many misfires it had. Most of the time you could not even clear the codes for the customer. I finally opened up one of the $500 readers they try to sell and started to use that instead. I am not a rich guy and I was trying to help people that did not have the extra $ to waste. I have been there. It is not fun to know you are going to loose your job because your car broke down.

[kens]

I had a 2000 Crown Vic, and had the same described issue with spark plug coils packs. I replaced them myself, no big deal.
Also, there was a run of intake manifolds that developed a oil leak that flooded the spark plug boots with oil, the rubber boot broke down and caused issue.
I bought the new type manifold ($250) and replaced it myself, a whole days project.
you may want to check if your car falls into the bad oil leaky manifold production run.

btw, I drove that car for over 15 years, 250,000 miles, was still running good when I sold it,
whether it was a old mans car or not, it ended up being the most economical car to drive for the 'total cost of ownership'
total cost of ownership is purchase + fuel + maintenance + tires + brakes + insurance + resale divided by years of use = total cost

[Battis]

Two jobs I had sold me on the big cars. I was a cop and I loved the Crown Vics. Then I drove a limo part time and was sold on the Towncars (like driving in your living room). I put some weight in the trunk of the Towncar during the winter and it goes just about everywhere I want to go.
One time I tried to stop a stolen Mustang 5.0 at night on the highway and the chase was on. I was doing about 120 mph (90,000 miles on the cop car) and the kid in the Mustang turned off his headlights and was going about 135 mph. I felt foolish so I turned off the pretty lights and went home.
That would have been a great Ford commercial.

[Handloader109]

Coils. Yes, replace them all if they haven't been replaced in the past 3 or so years. They break down, all of them, the cheap ones and the OEM ones. BTW, how do you determine which is failing at load with NO codes being thrown? YOU CAN'T..... Replace them all, Or do one at a time and HOPE you are getting the right one. BTW, it could be a couple.